/* Lusterna — styled after the Certora brand (certora.com). */
:root {
  --black: #0d0d0d;
  --green: #79f2a5;
  --cyan: #40dcff;
  --gray-300: #d4d4d4;
  --gray-500: #737373;
  --line: rgba(255, 255, 255, 0.12);
  --panel: #1e1e1e;
  --grad: linear-gradient(to bottom right, var(--green), var(--cyan));
  --font: "Satoshi", ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--black); color: #fff;
  font-family: var(--font); font-size: 16px; line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
h1, h2, h3, p, pre, ol { margin: 0; }
img { display: block; }
:focus-visible { outline: 2px solid var(--cyan); outline-offset: 3px; }

.wrap { max-width: 1040px; margin: 0 auto; padding: 0 24px; }
.grad-text { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }

/* Buttons — certora.com .btn-primary / .btn-secondary-dark */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  border: 2px solid transparent; border-radius: 0.2rem;
  padding: 0.5rem 1.1rem; font-weight: 600; line-height: 1.5rem;
  transition: filter 0.15s ease;
}
.btn:hover { filter: brightness(1.1); }
.btn-primary { background: var(--grad); color: var(--black); }
.btn-secondary { background: linear-gradient(var(--black), var(--black)) padding-box, var(--grad) border-box; font-weight: 500; }
.btn-sm { padding: 0.3rem 0.75rem; font-size: 0.875rem; line-height: 1.25rem; }

/* Nav */
.nav { border-bottom: 1px solid var(--line); }
.nav .wrap { display: flex; align-items: center; height: 64px; gap: 1rem; }
.brand { display: flex; align-items: center; gap: 0.55rem; font-weight: 700; font-size: 1.2rem; }
.brand-by {
  display: flex; align-items: center; gap: 0.4rem; padding-left: 0.9rem;
  border-left: 1px solid var(--line); color: var(--gray-500); font-size: 0.8rem;
}
.brand-by img { height: 17px; width: auto; }
.nav-links { margin-left: auto; display: flex; align-items: center; gap: 1.5rem; font-size: 0.9rem; color: var(--gray-300); }
.nav-links a:not(.btn):hover { color: #fff; }

/* Hero */
.hero { padding: 120px 0 112px; text-align: center; }
.badge {
  display: inline-block; margin-bottom: 1.75rem; padding: 0.2rem 0.75rem;
  border: 1px solid var(--line); border-radius: 999px;
  font-size: 0.8rem; color: var(--gray-300);
}
h1 { font-size: 4.25rem; line-height: 1.05; font-weight: 700; letter-spacing: -0.035em; }
.lead { max-width: 660px; margin: 1.75rem auto 0; font-size: 1.15rem; line-height: 1.65; color: var(--gray-300); }
.lead code { font-family: var(--mono); font-size: 0.9em; color: #fff; }
.cta { display: flex; gap: 0.875rem; justify-content: center; flex-wrap: wrap; margin-top: 2.5rem; }

/* Sections */
h2 { font-size: 2rem; font-weight: 700; letter-spacing: -0.02em; }
.sub { margin-top: 0.75rem; max-width: 640px; color: var(--gray-300); line-height: 1.65; }

.how { background: #fff; color: var(--black); padding: 96px 0; }
.how .sub { color: #4b5563; }
.stages { list-style: none; padding: 0; margin-top: 48px; display: grid; grid-template-columns: repeat(5, 1fr); border-top: 2px solid; border-image: var(--grad) 1; }
.stages li { padding: 20px 20px 0 0; }
.stages span { font-family: var(--mono); font-size: 0.8rem; color: #6b7280; }
.stages h3 { margin: 0.35rem 0 0.4rem; font-size: 1.15rem; font-weight: 700; }
.stages p { font-size: 0.93rem; line-height: 1.55; color: #4b5563; }

.start { padding: 96px 0 104px; }
.panel { margin-top: 36px; background: var(--panel); border: 1px solid var(--line); border-radius: 0.6rem; overflow: hidden; }
.panel-head {
  display: flex; align-items: center; padding: 0.55rem 1rem; background: #262626;
  border-bottom: 1px solid var(--line); font-family: var(--mono); font-size: 0.78rem; color: var(--gray-500);
}
.copy {
  margin-left: auto; font: 500 0.75rem var(--font); color: var(--gray-300); cursor: pointer;
  background: none; border: 1px solid var(--line); border-radius: 0.2rem; padding: 0.15rem 0.55rem;
}
.copy:hover { color: #fff; }
pre { padding: 1.2rem 1.25rem; overflow-x: auto; font: 0.86rem/1.75 var(--mono); color: #d4d4d4; }
.c { color: #6a9955; }
.links { margin-top: 1.5rem; display: flex; gap: 1.5rem; font-size: 0.95rem; }
.links a { color: var(--green); }
.links a:hover { text-decoration: underline; text-underline-offset: 3px; }

footer { border-top: 1px solid var(--line); padding: 28px 0; font-size: 0.85rem; color: var(--gray-500); }
footer .wrap { display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
footer a:hover { color: #fff; }

@media (max-width: 860px) {
  h1 { font-size: 3rem; }
  .stages { grid-template-columns: 1fr 1fr; border-top: 0; gap: 0 24px; }
  .stages li { border-top: 2px solid; border-image: var(--grad) 1; padding-bottom: 24px; }
}
@media (max-width: 560px) {
  .wrap { padding: 0 16px; }
  .brand-by, .nav-links a:not(.btn) { display: none; }
  .hero { padding: 80px 0 72px; }
  h1 { font-size: 2.4rem; }
  .lead { font-size: 1.05rem; }
  .how, .start { padding: 72px 0; }
  .stages { grid-template-columns: 1fr; }
  pre { font-size: 0.76rem; padding: 1rem; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }